// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
#define UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_

#include <stddef.h>
#include <stdint.h>

#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "ui/events/gesture_detection/gesture_detection_export.h"

namespace ui {

// Abstract class for a generic motion-related event, patterned after that
// subset of Android's MotionEvent API used in gesture detection.
class GESTURE_DETECTION_EXPORT MotionEvent {
public:
    enum Action {
        ACTION_NONE,
        ACTION_DOWN,
        ACTION_UP,
        ACTION_MOVE,
        ACTION_CANCEL,
        ACTION_POINTER_DOWN,
        ACTION_POINTER_UP,
    };

    enum ToolType {
        TOOL_TYPE_UNKNOWN,
        TOOL_TYPE_FINGER,
        TOOL_TYPE_STYLUS,
        TOOL_TYPE_MOUSE,
        TOOL_TYPE_ERASER
    };

    enum ButtonType {
        BUTTON_PRIMARY = 1 << 0,
        BUTTON_SECONDARY = 1 << 1,
        BUTTON_TERTIARY = 1 << 2,
        BUTTON_BACK = 1 << 3,
        BUTTON_FORWARD = 1 << 4,
        BUTTON_STYLUS_PRIMARY = 1 << 5,
        BUTTON_STYLUS_SECONDARY = 1 << 6,
    };

    // The implementer promises that |GetPointerId()| will never exceed
    // MAX_POINTER_ID.
    enum { MAX_POINTER_ID = 31,
        MAX_TOUCH_POINT_COUNT = 16 };

    virtual ~MotionEvent() { }

    // An unique identifier this motion event.
    virtual uint32_t GetUniqueEventId() const = 0;
    virtual Action GetAction() const = 0;
    // Only valid if |GetAction()| returns ACTION_POINTER_UP or
    // ACTION_POINTER_DOWN.
    virtual int GetActionIndex() const = 0;
    virtual size_t GetPointerCount() const = 0;
    virtual int GetPointerId(size_t pointer_index) const = 0;
    virtual float GetX(size_t pointer_index) const = 0;
    virtual float GetY(size_t pointer_index) const = 0;
    virtual float GetRawX(size_t pointer_index) const = 0;
    virtual float GetRawY(size_t pointer_index) const = 0;
    virtual float GetTouchMajor(size_t pointer_index) const = 0;
    virtual float GetTouchMinor(size_t pointer_index) const = 0;
    virtual float GetOrientation(size_t pointer_index) const = 0;
    virtual float GetPressure(size_t pointer_index) const = 0;
    virtual float GetTilt(size_t pointer_index) const = 0;
    virtual ToolType GetToolType(size_t pointer_index) const = 0;
    virtual int GetButtonState() const = 0;
    virtual int GetFlags() const = 0;
    virtual base::TimeTicks GetEventTime() const = 0;

    // Optional historical data, default implementation provides an empty history.
    virtual size_t GetHistorySize() const;
    virtual base::TimeTicks GetHistoricalEventTime(size_t historical_index) const;
    virtual float GetHistoricalTouchMajor(size_t pointer_index,
        size_t historical_index) const;
    virtual float GetHistoricalX(size_t pointer_index,
        size_t historical_index) const;
    virtual float GetHistoricalY(size_t pointer_index,
        size_t historical_index) const;

    // Get the id of the device which created the event. Currently Aura only.
    virtual int GetSourceDeviceId(size_t pointer_index) const;

    // Utility accessor methods for convenience.
    int GetPointerId() const { return GetPointerId(0); }
    float GetX() const { return GetX(0); }
    float GetY() const { return GetY(0); }
    float GetRawX() const { return GetRawX(0); }
    float GetRawY() const { return GetRawY(0); }
    float GetRawOffsetX() const { return GetRawX() - GetX(); }
    float GetRawOffsetY() const { return GetRawY() - GetY(); }

    float GetTouchMajor() const { return GetTouchMajor(0); }
    float GetTouchMinor() const { return GetTouchMinor(0); }

    // Returns the orientation in radians. The meaning is overloaded:
    // * For a touch screen or pad, it's the orientation of the major axis
    //   clockwise from vertical. The return value lies in [-PI/2, PI/2].
    // * For a stylus, it indicates the direction in which the stylus is pointing.
    //   The return value lies in [-PI, PI].
    float GetOrientation() const { return GetOrientation(0); }

    float GetPressure() const { return GetPressure(0); }
    float GetTilt() const { return GetTilt(0); }
    ToolType GetToolType() const { return GetToolType(0); }

    // O(N) search of pointers (use sparingly!). Returns -1 if |id| nonexistent.
    int FindPointerIndexOfId(int id) const;

    // Note that these methods perform shallow copies of the originating events.
    // They guarantee only that the returned type will reflect the same
    // data exposed by the MotionEvent interface; no guarantees are made that the
    // underlying implementation is identical to the source implementation.
    scoped_ptr<MotionEvent> Clone() const;
    scoped_ptr<MotionEvent> Cancel() const;
};

} // namespace ui

#endif // UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
